Infiniti M45

Mercedes-Benz, Lexus, BMW and Cadillac. The mere mention of these luxury brands summons a clear impression of what they stand for—and, quite likely, what their products look like. Say the name Infiniti, and what comes to mind is a vague picture of the Nissan's luxury division in search of an identity for 15 years. The quest for its rightful place in the luxury pantheon may have borne fruit with the 2006 M45, a sedan that breathes fire, spins tires and still delivers looks and luxe.

Infiniti had come close to the mark recently with the sporty G35, the quirky crossover FX45 and the previous-generation M, a definite sleeper, sporty, sleek, but not quite distinctive enough in a crowded luxury market. Infiniti didn't repeat that mistake. The 2006 model is both visually striking—featuring the Japanese automaker's new "vibrant design" theme—and technologically sophisticated.

The '06 M features a voice-activated DVD navigation system, hands-free Bluetooth phone technology, laser-guided active cruise control and adaptive forward lighting, which follows the steering wheel to aim into corners. Infiniti also will be offering an all-new Lane Departure Warning system, which uses a camera mounted behind the rearview mirror to see if you inadvertently cross a lane marker. Commit a "violation," and you'll get a gentle chiding.

The heart of the '06 M45 is a 335-horsepower, 4.5-liter aluminum V-8 that emits the low, throbbing roar that one normally associates with a classic muscle car. The engine boasts 32 variably timed titanium valves, and it's mated to a 5-speed automatic that's smart enough to blip the throttle when shifted in manual mode.

Step down on the accelerator and you'll find yourself sinking deep into the sporty leather seats. Steering is a little light, but sure and responsive. The sedan's chassis is extraordinarily stiff, something we discovered during a hard drive through the winding mountain passes connecting California's Napa and Sonoma valleys. The Sport edition adds another slick touch, an active rear steering system that handles curves with uncanny precision.

Infiniti doesn't offer all-wheel-drive on the M45—yet. An AWD option will, however, be available for the V-6-powered M35, with an impressive 280 hp that's not much of a sacrifice for those who opt for the V-6. It will still blast the big sedan from 0 to 60 in barely 6.5 seconds.

Talk that the aging Infiniti flagship, the Q45, might be replaced by the sportier M series was apparently unfounded. Nevertheless, expect the newer car to dominate the sales chart until a replacement Q is unleashed. If our initial experience holds up once the new M45 hits showrooms, this is very likely to be the car that makes Infiniti's niche in the luxury market.